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MI CAN BE RULED OUT WITHIN 12 HOURS IN SOME PATIENTS.

Most patients admitted to coronary care units for acute chest pain subsequently "rule out" for a myocardial infarction after an observation period of 24 to 48 hours. A new analysis of data from patients enrolled in the Multicenter Chest Pain Study suggests that some patients can be safely transferred out of the CCU after 12 hours.

The probability of MI at the time of admission to the emergency room was first determined in a group of 976 patients according to a published algorithm. Patients in whom the predicted probability of MI was low (less than 7 percent) had an even lower risk of MI if they had normal levels of cardiac enzymes and no recurrent ischemic pain during the first 12 hours of hospitalization. When these guidelines were applied to a new group of 2684 patients, 771 qualified as candidates for a 12-hour observation period. Of these patients, only four (0.5 percent) subsequently developed nonfatal MI, and three experienced fatal cardiac arrest, the deaths occurring 3 to 5 days after admission. Rates of other major cardiovascular complications were also low.

Because many patients who were eligible for early discharge under the study criteria actually remained in the CCU, it is possible that outcomes would not have been as good had early discharge been attempted. Nevertheless, this study provides useful data to guide clinicians in the early discharge of patients with a low probability of MI.

— ALK

Published in Journal Watch General Medicine May 3, 1991

Citation(s):

Eagle KA. Medical decision making in patients with chest pain. N Engl J Med 1991 May 2 324 1282-1283.

• Medline abstract (Free)

Lee TH et al. Ruling out myocardial infarction: a prospective multicenter validation of a 12-hour strategy for patients at low risk. N Engl J Med 1991 May 2 324 1239-1246.

• Medline abstract (Free)